Skip to main content
ICD-10/G56.40

G56.40 ICD-10-CM Code: Causalgia of unspecified upper limb

G56.40 is the authoritative medical code for Causalgia of unspecified upper limb. This classification is used in medical billing and clinical recording to specify the clinical criteria for causalgia of unspecified upper limb (ICD-10-CM G56.40), ensuring healthcare documentation aligns with current federal coding standards.

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0 (FY2026), Appendix B.

  • MS-DRG 073 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITH MCC (MDC 01)
  • MS-DRG 074 — CRANIAL AND PERIPHERAL NERVE DISORDERS WITHOUT MCC (MDC 01)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Code Set: Valid FY2026 and FY2027. FY2026 took effect October 1, 2025.

Official Registry Overview & Definition

Causalgia of unspecified upper limb is a billable ICD-10-CM diagnosis code (G56.40). Excludes1 (not coded here): complex regional pain syndrome I of lower limb (G90.52-); complex regional pain syndrome I of upper limb (G90.51-); complex regional pain syndrome II of lower limb (G57.7-); reflex sympathetic dystrophy of lower limb (G90.52-); reflex sympathetic dystrophy of upper limb (G90.51-); current traumatic nerve disorder - see nerve injury by body region; current traumatic nerve, nerve root and plexus disorders - see Injury, nerve by body region; neuralgia NOS (M79.2); neuritis NOS (M79.2); peripheral neuritis in pregnancy (O26.82-); radiculitis NOS (M54.1-).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for G56.40 in the official ICD-10-CM tabular list.

Excludes1 — Not Coded Here

Conditions that can never be reported with this code; the two are mutually exclusive.

  • complex regional pain syndrome I of lower limb (G90.52-)
  • complex regional pain syndrome I of upper limb (G90.51-)
  • complex regional pain syndrome II of lower limb (G57.7-)
  • reflex sympathetic dystrophy of lower limb (G90.52-)
  • reflex sympathetic dystrophy of upper limb (G90.51-)
  • current traumatic nerve disorder - see nerve injury by body region
  • current traumatic nerve, nerve root and plexus disorders - see Injury, nerve by body region
  • neuralgia NOS (M79.2)
  • neuritis NOS (M79.2)
  • peripheral neuritis in pregnancy (O26.82-)
  • radiculitis NOS (M54.1-)

Frequently Asked Questions (FAQ) & Clinical Guidance

What can't be coded together with G56.40?

Per official ICD-10-CM Excludes1 instructions, G56.40 must not be reported together with: complex regional pain syndrome I of lower limb (G90.52-); complex regional pain syndrome I of upper limb (G90.51-); complex regional pain syndrome II of lower limb (G57.7-); reflex sympathetic dystrophy of lower limb (G90.52-).

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G56.40 in its code family, with their registry titles.

  • G56.30 — Lesion of radial nerve, unspecified upper limb
  • G56.31 — Lesion of radial nerve, right upper limb
  • G56.32 — Lesion of radial nerve, left upper limb
  • G56.33 — Lesion of radial nerve, bilateral upper limbs
  • G56.4 — Causalgia of upper limb
  • G56.41 — Causalgia of right upper limb
  • G56.42 — Causalgia of left upper limb
  • G56.43 — Causalgia of bilateral upper limbs
  • G56.8 — Other specified mononeuropathies of upper limb
  • G56.80 — Other specified mononeuropathies of unspecified upper limb

View all codes in the G56 family